Abstract: A power converter and control circuit are provided. The control circuit has a power controller for turning on the power switch to maintain a desired output voltage and mode selection switch provides a mode selection signal. Depending on the magnitude of an input voltage of the power converter, in which the mode selection circuit compares the input voltage of the power converter with a reference voltage, a modulation controller is configured to turn on a modulation switch to activate the capacitor according to the mode selection signal.

Abstract: A power converter includes a power switch controlling current flow in the power converter and a variable capacitance coupled in parallel to the power switch. The variable capacitance is configured to add a frequency jitter to the power converter.

Abstract: A power converter and control circuit are provided. The control circuit has a power controller for turning on the power switch to maintain a desired output voltage and mode selection switch provides a mode selection signal. Depending on the magnitude of an input voltage of the power converter, in which the mode selection circuit compares the input voltage of the power converter with a reference voltage, a modulation controller is configured to turn on a modulation switch to activate the capacitor according to the mode selection signal.

Abstract: A method for controlling a power converter includes turning on a power switch to maintain a desired output voltage, wherein the power switch is coupled to a primary winding to control a primary current flow and the output voltage is provided by a secondary winding. The method also includes adding a capacitance in parallel to the power switch at a time determined by a magnitude of an input voltage to the power converter. Here, the timing of adding the capacitance depends on the operation mode of the power controller. In a low input voltage mode, the capacitance is added in a demagnetization-time during which the secondary winding discharges. In a high input voltage mode, the capacitance is added in a discontinuous time.

Abstract: A power converter includes a power switch controlling current flow in the power converter and a variable capacitance coupled in parallel to the power switch. The variable capacitance is configured to add a frequency jitter to the power converter.

Abstract: A power converter includes a power switch controlling current flow in the power converter and a variable capacitance coupled in parallel to the power switch. The variable capacitance is configured to add a frequency jitter to the power converter.

Abstract: A method for controlling a power converter includes turning on a power switch to maintain a desired output voltage, wherein the power switch is coupled to a primary winding to control a primary current flow and the output voltage is provided by a secondary winding. The method also includes adding a capacitance in parallel to the power switch at a time determined by a magnitude of an input voltage to the power converter. Here, the timing of adding the capacitance depends on the operation mode of the power controller. In a low input voltage mode, the capacitance is added in a demagnetization-time during which the secondary winding discharges. In a high input voltage mode, the capacitance is added in a discontinuous time.

Abstract: A power converter includes a power switch controlling current flow in the power converter and a variable capacitance coupled in parallel to the power switch. The variable capacitance is configured to add a frequency jitter to the power converter.

Abstract: A Quasi-Resonant (QR) converter includes a power switch controlling the primary current flow and a time-varying capacitance coupled in parallel to the power switch. The time-varying capacitance is configured to add a frequency jitter to the frequency switch of the converter.

Abstract: A Quasi-Resonant (QR) converter includes a power switch controlling the primary current flow and a time-varying capacitance coupled in parallel to the power switch. The time-varying capacitance is configured to add a frequency jitter to the frequency switch of the converter.

Abstract: A power controller makes use of a line-voltage detection method to perform brown-out protection and brown-in mechanism. The power controller has a high-voltage node connected via a current-limiting resistor to a line voltage, and a high-voltage startup transistor connected to the high-voltage node. The input voltage at the high-voltage node is divided to provide a fraction result. An offset current flowing through the high-voltage startup transistor and the current-limiting resistor is provided in response to the fraction result. The offset current is stopped in response to the fraction result when the offset current flows through the high-voltage startup transistor and the current-limiting resistor.

Abstract: A power controller makes use of a line-voltage detection method to perform brown-out protection and brown-in mechanism. The power controller has a high-voltage node connected via a current-limiting resistor to a line voltage, and a high-voltage startup transistor connected to the high-voltage node. The input voltage at the high-voltage node is divided to provide a fraction result. An offset current flowing through the high-voltage startup transistor and the current-limiting resistor is provided in response to the fraction result. The offset current is stopped in response to the fraction result when the offset current flows through the high-voltage startup transistor and the current-limiting resistor.

Abstract: A method providing short-circuit protection and a flyback converter utilizing the same wire are disclosed. The a method, adopted by a flyback converter, includes a transformer, including generating a feedback voltage according to an output voltage output from a secondary winding of the transformer; controlling a primary current through a primary winding of the transformer based on the feedback voltage; determining a sense voltage according to the primary current; determining a short circuit based on the sense voltage; setting the primary current according to a short-circuit sense voltage limit when a short circuit occurs; and setting the primary current according to a normal sense voltage limit when a short circuit does not occur.

Abstract: A constant current controller for a constant current power module, including: a demagnetization sensing unit, used for detecting the voltage variation of a detection signal to generate a discharging time signal having an active period corresponding to a secondary side discharging time, wherein the detection signal is derived from an auxiliary coil; a secondary side current sensing unit, used for detecting a peak value of a current sensing signal, and providing an output current according to the peak value of the current sensing signal under the control of the discharging time signal, wherein the current sensing signal is corresponding to a primary side current; and an error current generator, used for generating an error current according to the difference between the output current and a reference current, wherein the error current is converted to a threshold voltage by a first capacitor.

Abstract: A cascoded current regulator, including: a first load circuit, having a first load and a current source unit; and a second load circuit, being cascaded with the first load circuit and having a second load and a current mirror unit, wherein a first current flowing through the first load and a second current flowing through the current source unit are controlled by a control voltage, and a third current flowing through the second load and a fourth current flowing through the current mirror unit are generated according to the second current.

Abstract: A constant current controller for a constant current power module, including: a demagnetization sensing unit, used for detecting the voltage variation of a detection signal to generate a discharging time signal having an active period corresponding to a secondary side discharging time, wherein the detection signal is derived from an auxiliary coil; a secondary side current sensing unit, used for detecting a peak value of a current sensing signal, and providing an output current according to the peak value of the current sensing signal under the control of the discharging time signal, wherein the current sensing signal is corresponding to a primary side current; and an error current generator, used for generating an error current according to the difference between the output current and a reference current, wherein the error current is converted to a threshold voltage by a first capacitor.

Abstract: A cascoded current regulator, including: a first load circuit, having a first load and a current source unit; and a second load circuit, being cascaded with the first load circuit and having a second load and a current mirror unit, wherein a first current flowing through the first load and a second current flowing through the current source unit are controlled by a control voltage, and a third current flowing through the second load and a fourth current flowing through the current mirror unit are generated according to the second current.

Abstract: A power conversion controller having a novel power factor correction mechanism, including: a normalization unit, used to generate a normalized signal according to a line voltage by multiplying the line voltage with a normalizing gain, wherein the normalizing gain is proportional to the reciprocal of the amplitude of the line voltage; a reference current generation unit, coupled to the normalization unit to generate a reference current signal by performing an arithmetic operation, wherein the arithmetic operation involves the normalized signal; and a gate drive signal generation unit, used to generate a gate drive signal, wherein the duty of the gate drive signal is determined by a voltage comparison of the reference current signal and a current sensing signal.

Abstract: A high side controller capable of sensing input voltage and output voltage of a power conversion circuit, including: a first switch, having a control end and two channel ends, the control end being coupled to a gate signal, and one of the two channel ends being coupled to a voltage signal, wherein the voltage signal is proportional to a negative version of the input voltage when the gate signal is active; an inverting amplification circuit, having an input end coupled to the other one of the two channel ends, and an output end for providing a first processed voltage; and a first sample and hold circuit, having a control input end coupled to the gate signal, an input end coupled to the first processed voltage, and an output end for providing a first sample voltage.

Abstract: An LED lighting circuit capable of preventing thermal breakdown, including: an LED module, having a top end coupled to a line voltage; and a controller, coupled to the line voltage and a bottom end of the LED module, the controller including: an amplifier, having a positive input end coupled to an adjustable reference voltage; a transistor, having a gate terminal coupled to an output end of the amplifier, a first channel terminal coupled to the bottom end of the LED module, and a second channel terminal coupled to a negative input end of the amplifier; a current sensing resistor, coupled between the second channel terminal and a ground; and a reference voltage generator, used for generating the adjustable reference voltage according to the line voltage.